When it comes to ultralight backpacks, there are basically two categories of packs: frameless & internal frame packs. External frames are a different animal altogether and, because I have no experience with them, I can not give an objective opinion of them. Yet in the world of ultralight hiking & backpacking, external packs do not generally have a place. This article reveals some basic comparisons with frameless & internal frame packs but, by no means, is this a comprehensive report.
First off, what are the main differences of frameless & internal frame packs? Frameless packs do not have what are called stays, or a basic frame outline which supports the structure. These are usually made from aluminum, fiberglass or carbon fiber. Strength is maintained with these lightweight materials. It's generally accepted that a pack at 3 pounds or less is considered ultralight, and some may even stretch that to 3.5-4 pounds. There are many quality-built packs within the realms of these two categories. Understanding what kind of hiker or backpacker you are will go a long way in determining which type of pack you should buy.
Frameless packs basically can not stand on their own, and when empty, crumble like an empty duffel bag. They are made from thin nylon, strong & abrasion resistant. These packs have become incredibly popular over the last several years, and with the advent of newer materials, these packs just seem to keep getting lighter & stronger. I've kind of had a love-hate relationship with my Granite Gear Virga backpack. It's a frameless pack, and when full, can comfortably carry up to 30 lbs. I've had it stuffed to more than 35 lbs of gear, which is not recommended by the manufacturer. Loading the pack first thing in the morning, after just rolling up my tent & cold, maybe a bit cranky from a not-so-good night's sleep; more than once brought me near cursing. This is the most common downside of frameless packs, and many people do not consider it a downside, just a unique character trait. The idea behind loading a frameless pack is to take a rolled foam sleeping pad and place it long ways into the pack, allowing the pad to unroll and therefore shore up the sides somewhat, for support.
Internal frame backpacks can generally carry larger loads than frameless packs & have more support in the back & waistbelt areas of the pack. A number of manufacturers build good internal frame packs. These packs are commonly believed to hold packed gear closer to your body than external frame packs do, but are comparable with how they fit with newer frameless packs. Both packs sit against the back, allowing for minimal ventilation in this area. Even with the newer, "breathable" pack rests on the market today, a person's back will become wet with sweat from wearing the pack. This is something that manufacturers have tried to mitigate with modern designs, but it's an inevitable point in wearing either of these type of packs.
Internal frame packs many times have more pockets for organizing gear than do frameless packs, but both pack types generally have a single compartment for storing gear. As backpack designs become more efficient, many frameless packs are integrated with better waistbelts, comparing to and even surpassing many internal frame backpacks. Both types of gear are fitted with numerous compression straps, allowing for tightening the loads and minimize shifting.
So how are you to decide which pack is best for you? If you've never backpacked before, or are just thinking of switching from one style of pack to another, then here are a few suggestions that may help you in your decision. Much of this is common sense, and doing a little research either online or in speaking with an outdoor professional, can help a great deal in making an educated choice.
1.Read several reviews, both online & in printed magazines. Consider the sources of the information, whether they are from experienced users & manufacturers, or just empty reviews from those who've never actually used the gear.
2.Go to 2 or 3 outfitters and try on different styles & manufacturers of backpacks. Reviews can be very helpful, yet without the tactile experience of wearing a piece of gear, an informed decision can be difficult to make.
3.Borrow different packs from friends or relatives. If someone you know has a pack you think may suit you well, ask if they'd let you borrow it for a day or even a couple of hours. This may save you a lot of money in the long run.
4.Realize this: there is no "perfect pack." Too many forums are filled with posts from hikers telling how they've found the perfect pack. Yet a little more reading will reveal some changes or modifications they've made to this particular backpack. If they mention any dislikes with a piece of gear, then it's not perfect. In fact, no gear is perfect. If it was, there'd never be a need to replace it due to wear & tear. Find a backpack that fits your needs as much as possible. From there, it's possible with some modifying, the pack can be made to suit you even better.
5.Don't be afraid of buying the "wrong pack." There's an inherent fear we have, which I believe is planted & nurtured by the media & world in general, that second-guesses our decision-making ability. There's a feeling that maybe we did not buy the gear we should have, or maybe this other gear would've been a better choice. Sometimes this thought is true, as we all have made less than ideal choices in life. But buying a backpack which in turn we're unhappy with, this is not the end of the world, or even a major problem. You can always sell an unwanted item online or give it to a friend who may need it. You can even become a gear tester and try out gear for free! If you do not like the piece of gear, then you have not lost anything but time. Of course, there are some requirements needed to become a gear tester, so you may want to look into doing this.
So, if you're looking for a new backpack, or may want to try a different style of pack, do some research & ask your local outfitter for some help. Do several online searches & weigh the pros & cons. Realize there is no perfect choice, and that many different options will help fill the same basic needs. Get some gear & get out there!